Recently, a smart building equipped with various sensors has become an issue. In a smart building, various sensors each obtaining certain information are used.
Generally, such a smart building is a large building, and many sensors are placed in a large inner space thereof. Therefore, considering the burden of cost caused by wiring, damage to a building and difficulty in design, in a smart building, a section where sensors are connected via wire is minimized and communication between sensors or between a sensor and an AP is wirelessly performed.